Elevator belt assembly with noise reducing groove arrangement

ABSTRACT

An elevator load bearing assembly ( 20 ) includes a plurality of cords ( 22 ) within a jacket ( 24 ). The jacket has a plurality of grooves ( 32, 34, 36, 38 40 ) spaced along the length of the belt assembly. Each groove has a plurality of portions ( 50, 52, 54, 56 ) aligned at an oblique angle (A, B) relative to a longitudinal axis ( 48 ) of the belt ( 20 ). In one example, the grooves are separated such that there is no longitudinal overlap between adjacent grooves. In another example, transitions ( 60, 64 ) between the obliquely aligned portions are at different longitudinal positions on the belt. Another example includes a combination of the different longitudinal positions and the non-overlapping groove placement.

BACKGROUND OF THE INVENTION

This invention generally relates to load bearing members for use inelevator systems. More particularly, this invention relates to anelevator belt assembly having a specialized groove arrangement.

Elevator systems typically include a cab and counterweight that movewithin a hoistway to transport passengers or cargo to different landingswithin a building, for example. A load bearing member, such as roping ora belt typically moves over a set of sheaves and supports the load ofthe cab and counterweight. There are a variety of types of load bearingmembers used in elevator systems.

One type of load bearing member is a coated steel belt. Typicalarrangements include a plurality of steel cords extending along thelength of the belt assembly. A jacket is applied over the cords andforms an exterior of the belt assembly. Some jacket applicationprocesses result in grooves being formed in the jacket surface on atleast one side of the belt assembly. Some processes also tend to causedistortions or irregularities in the position of the steel cordsrelative to the exterior of the jacket along the length of the belt.

FIG. 7, for example, illustrates both of these phenomena. As can beseen, the spacing between the exterior of the jacket 200 and the cords210 varies along the length of the belt. As can be appreciated from theillustration, the cords 210 are set within the jacket as if theycomprise a series of cord segments of equal length corresponding to thegroove spacing. FIG. 7 includes an exaggeration of the typical physicalcord layout for purposes of illustration. The actual distortions orchanges in the position of the cords relative to the jacket outersurfaces may not be discernable by the human eye in some examples.

When conventional jacket application processes are used, the manner inwhich the cords are supported during the jacket application processtends to result in such distortion in the geometry or configuration ofthe cords relative to the jacket outer surfaces along the length of thebelt.

While such arrangements have proven useful, there is need forimprovement. One particular difficulty associated with such beltassemblies is that as the belt moves in the elevator system, the groovesand the cord placement in the jacket interact with other systemcomponents such as the sheaves and generate undesirable noise, vibrationor both. For example, as the belt assembly moves at a constant velocity,a steady state frequency of groove contact with the sheaves creates anannoying, audible tone. The repeated pattern of changes in the cordspacing from the jacket outer surfaces is believed to contribute to suchnoise generation.

An alternative arrangement is required to minimize or eliminate theoccurrence of vibrations or an annoying tone during elevator systemoperation. This invention addresses that need.

SUMMARY OF THE INVENTION

In general terms, this invention is a belt assembly for use in anelevator system. The belt assembly includes a plurality of cordsextending generally parallel to a longitudinal axis of the belt. Ajacket over the cords includes a plurality of grooves that areconfigured and spaced to minimize the occurrence of any annoying audiblenoise during elevator operation.

One example belt designed according to this invention includes aplurality of grooves on at least one surface of the jacket. Each groovehas a plurality of portions aligned at an oblique angle relative to thebelt axis. Each groove has a transition between adjacent portions. Eachgroove has a plurality of such transitions and each transition is at adifferent longitudinal position on the belt.

In one example, the different longitudinal positions of the transitionsare achieved by using different oblique angles for different portions ofthe groove. Having the transitions at different longitudinal positionsreduces the noise-generating impact between the belt and sheaves in theelevator system.

Another example belt designed according to this invention includes aplurality of grooves on at least one surface of the jacket. Each groovehas a plurality of portions aligned at an oblique angle relative to thebelt axis. The grooves are spaced apart such that adjacent grooves areon opposite sides of a longitudinal position on the belt.

In one example, adjacent grooves are on opposite sides of an imaginaryline that extends transverse to the belt axis. Such a spacing betweenthe grooves avoids any overlap between any portion of a groove and anadjacent groove. Maintaining such spacing between grooves reduces thenoise-generating energy associated with the impact between the groovesand a sheave as the belt wraps around a portion of the sheave duringelevator system operation.

In one example, the grooves are longitudinally spaced such that spacingsbetween the grooves vary along the length of the belt. Having differentspacings between adjacent grooves eliminates the steady state frequencyof groove contact with other system components, which is a majorcontributor to the potential for undesirable noise or vibration duringelevator operation.

A belt assembly designed according to this invention may include theinventive spacing between grooves, the inventive angular alignment ofgroove segments or a combination of both. The various features andadvantages of this invention will become apparent to those skilled inthe art from the following detailed description of the currentlypreferred embodiments. The drawings that accompany the detaileddescription can be briefly described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a portion of an example belt assemblydesigned according to an embodiment of this invention.

FIG. 2 is a cross-sectional illustration taken along the lines 2-2 inFIG. 1.

FIG. 3 is a planar, schematic illustration of the groove arrangement ofthe embodiment of FIG. 1 showing selected geometric features.

FIG. 4 is an enlarged view of the encircled portion of FIG. 1, whichschematically illustrates an example groove cross sectionalconfiguration.

FIG. 5 schematically illustrates an alternative groove arrangement.

FIG. 6 schematically illustrates a method of making a belt designedaccording to an embodiment of this invention.

FIG. 7 schematically illustrates a typical cord geometry relative toouter surfaces on a belt jacket according to the prior art.

FIG. 8 schematically illustrates selected portions of an exampleelevator system.

DETAILED DESCRIPTION

FIGS. 1 and 2 schematically illustrate a belt assembly 20 that isdesigned for use in an elevator system. A plurality of cords 22 arealigned generally parallel to a longitudinal axis of the belt assembly20. In one example, the cords 22 are made of strands of steel wire.

A jacket 24 covers over the cords 22. The jacket 24 preferably comprisesa polyurethane-based material. A variety of such materials arecommercially available and known in the art to be useful for elevatorbelt assemblies. Given this description, those skilled in the art willbe able to select a proper jacket material to suit the needs of theirparticular situation.

The jacket 24 establishes an exterior length, L, width, W, and athickness, t, of the belt assembly 20. In one example, the width W ofthe belt assembly is 60 millimeters, the thickness t is 3 millimetersand the length L is dictated by the particular system where the beltwill be installed. In the same example, the cords 22 have a diameter of1.65 millimeters. In this example, there are twenty-four cords. Thecords 22 preferably extend along the entire length L of the assembly.

The jacket 24 includes a plurality of grooves 30, 32, 34, 36, 38, 40 and42 on at least one side of the jacket 24. In the illustrated example,the grooves extend across the entire width of the belt assembly.

The grooves result from some manufacturing processes, many of which arewell known in the art, that are suitable for forming the belt assembly20. As can best be appreciated from FIG. 2, the grooves extend betweenan exterior surface of the jacket 24 and the surface of the cords 22facing the same exterior surface of the jacket.

Referring to FIGS. 1 and 3, this example embodiment has grooves that aregenerally W-shaped. Each groove includes a plurality of portions thatare aligned at an oblique angle relative to the longitudinal axis 48 ofthe belt. Taking the groove 34 as an example, a first portion 50 extendsat an oblique angle A in a first longitudinal direction. A secondportion 52 extends in an opposite longitudinal direction at the obliqueangle A. A third portion 54 extends in the same direction as the firstportion 50 but at a second oblique angle B. A fourth portion 56 extendsin an opposite longitudinal direction at the second oblique angle B.

In one example, the angle A is approximately 50°. In the same example,the angle B is approximately 53.5°. Utilizing different oblique anglesfor different portions of the groove allows for strategic positioning oftransitions between the obliquely aligned portions.

The groove 34 in FIG. 3, for example, has a first transition 60, asecond transition 62 and a third transition 64. Each transition joinstwo adjacent obliquely angled portions of the groove. Because the firstoblique angle A is different than the second oblique angle B, thelongitudinal position of the transition 60 is different than thelongitudinal position of the transition 64. “Longitudinal position” asused in this description refers to a position on the belt along thelength of the belt (i.e., in a direction parallel to the axis 48).

For example, the distance between the line 70, which extends transverseto the belt axis 48 across the width of the belt, and the transition 60is different than the distance between the line 70 and the transition64. In this example, the transition 60 is closer to the line 70 than thetransition 64 because the angle A is smaller than the angle B. The line70 is provided for discussion purposes and does not indicate a physicalline on the belt.

Keeping the transitions at different longitudinal positions effectivelychanges the phase of the two halves of the groove. Having thetransitions out of phase tends to cancel the energy associated withcontact between the transitions and sheaves. Therefore, the inventivearrangement reduces vibration and noise in an elevator system.

As shown in the illustrated example, the transitions are essentiallypeaks along the groove. In this example, each transition is curvilinear.Having a curved transition between obliquely angled portions of thegrooves that extend in opposite directions reduces the vibration andnoise-generating impact energy associated with the grooves contacting asheave in the elevator system.

As can be appreciated from FIG. 3, in the illustrated example, theportions 50, 52, 54 and 56 are linear over the majority of their length.The linear portions are aligned at the selected oblique angle or angles,depending on the desired groove configuration. This invention is notlimited to a belt having grooves with truly linear portions. In anexample assembly where the portions are at least somewhat curvilinear,tangent lines associated with such a curvilinear portion preferably areat selected oblique angles relative to the belt axis.

In the example of FIG. 3, the spacing 72 between adjacent grooves (i.e.,between the groove 32 and the groove 34, between the groove 34 and thegroove 36 and between the groove 36 and the groove 38, respectively) isselected such that there is no overlap between any portion of anyadjacent groove. Considering the line 70 as indicating a longitudinalposition on the belt 20, the grooves 36 and 38 are on opposite sides ofthe line 70. Accordingly, there is no overlap between any portion of thegroove 36 and any portion of the groove 38. Keeping the entire groove 36longitudinally spaced from the entire groove 38 reduces the vibrationand noise-generating energy associated with the impact between thegrooves and a sheave during elevator system operation.

The spacing 72 between the grooves preferably prevents any overlapbetween adjacent grooves along the entire length of the belt. In someexamples, the spacing 72 may be consistent along the entire length ofthe belt. In other examples, the spacing 72 varies between grooves in aselected pattern as will be described below.

In addition to the different longitudinal positions of the transitionsand the absence of any longitudinal overlap between adjacent grooves, abelt designed according to this invention may include further vibrationand noise reducing features. FIG. 4, for example, shows one embodimentof a groove configuration where the interface between the groove and theexterior surface on the jacket 24 includes a rounded edge or fillet 74.Using such a rounded edge 74 reduces the vibration and noise producingenergy associated with the impact between the groove and a surface on asheave in the elevator system. In this example, the fillets 74 have aradius of curvature that is in a range from about 0.05 to 0.15millimeters.

In the example of FIG. 4, sidewalls 76 of the groove 38 extend from theexterior surface of the jacket 24 to the bottom 78 of the groove, whichis directly adjacent a surface of the cords 22. The intersectionsbetween the sidewalls 76 and the bottom 78 in this example includerounded surfaces having the same radius of curvature as the fillets 74.

In one example, a 0.1 millimeter radius of curvature is used for thefillets 74 and the transitions between the sidewalls and the bottom 78.One example arrangement has the sidewalls 76 arranged at an angle C thatis approximately 30°. An example height of the groove is 0.7 millimetersand an example width S of the groove is 0.7 millimeters.

The configuration of the grooves is dictated in some examples by theshape of the cord supports used during the belt manufacturing process.Those skilled in the art who have the benefit of this description willbe able to select from among commercially available materials used formaking jackets on elevator belts and be able to configure themanufacturing equipment or other groove-forming equipment to achieve thedesired groove profile to meet the needs of their particular situation.

FIG. 5 shows another example belt 20 designed according to thisinvention. In this example, each groove has only two portions 80 and 82extending in opposite longitudinal directions but at the same obliqueangle A. A single transition 84 joins the portions 80 and 82. In thisexample, both portions 80 and 82 extend at the same angle A and thetransition 84 is aligned at the center line 85, which is coincident withthe longitudinal axis of the belt. Of course, other configurations arewithin the scope of this invention.

In this example, the space 86 between adjacent grooves is selected sothat adjacent grooves are on opposite sides of a longitudinal positionon the belt 20. For example, the line 88 indicates a longitudinalposition, which is taken transversely to the axis 85 of the belt. In oneexample, such a line could be drawn between every set of adjacentgrooves and there would be no longitudinal overlap between the groovesbecause each groove would be on an opposite side of such a line.Arranging the grooves to avoid longitudinal overlap reduces the energyassociated with impact between the grooves and the surface of a sheavein an elevator system.

In one example, an embodiment such as that shown in FIG. 5 is used for abelt having a width W that is approximately 30 millimeters while a belthaving a configuration like that shown in FIG. 3 is used for a belt withW of approximately 60 millimeters. The selection of belt width depends,in part, on the expected duty loads for the elevator system in which thebelt will be employed.

FIG. 6 schematically illustrates one example method of making elevatorbelts designed according to this invention. A 60 millimeter wide belt 90having a groove configuration as shown in the embodiment of FIG. 3, forexample, is cut in half along the longitudinal axis of the belt using acutting station 92. Two belts 94 and 96 result, which haveconfigurations as shown in FIG. 5, for example. This strategy for makingelevator belts allows for the same manufacturing equipment to be used toproduce belts having a 60 millimeter wide width and 30 millimeter widewidth, for example.

One example elevator system 220 that includes belts 20 designedaccording to this invention includes a plurality of belts 20 in parallelthat move simultaneously over the sheaves 230. The plurality of belts inthis example include obliquely angled groove portions 232 that aredifferent angles for at least two of the belts as shown at 240. Havingdifferent oblique angles on the belts provides the benefit of keepingthe transitions on one belt at different longitudinal positions than thetransitions on another belt. Such longitudinal positioning effectivelychanges the phase of at least the two belts having different obliqueangles. Having the transitions out of phase allows for the energyassociated with contact between the transitions on one belt and thesheaves to effectively cancel out the energy associated with suchcontact between the sheaves and the other belt.

In one example, every belt has groove portions angled at a differentoblique angle than the other belts. In another example, the same obliqueangle is used on the belts, however, the belts are aligned relative toeach other in the system such that the groove transitions on one beltare at different longitudinal positions than the groove transitions onat least one other belt.

An additional vibration and noise reducing feature of a belt designedaccording to some example embodiments of this invention includes havingthe grooves spaced apart different distances so that there are differentspacings between various grooves. Referring to FIG. 2, for example, afirst spacing 144 separates the groove 30 from the adjacent groove 32. Adifferent spacing 146 separates the groove 32 from the adjacent groove34. Similarly, at least some of the spacings 148, 150, 152 and 154 varyin size.

It is not necessary that all of the illustrated spacings are different,however, it is preferred to provide at least several different spacingsalong the length of the belt assembly. As a practical matter, a repeatedpattern of the varying spacings will typically extend along the entirelength of the belt assembly 20. Depending on the particulars of the beltassembly and the equipment used to form and apply the jacket 24, thepattern of different spacings will repeat at different intervals.Preferably, the interval of pattern repetition will be as large as themanufacturing equipment allows. In one example, there is a selectedpattern of different spacings that repeats about every fifty grooves orevery two meters of belt length. Within each two meter section, thespacings between adjacent grooves are selected to be varying andnon-periodic.

In one example embodiment, the spacings between the grooves are selectedto be 13.35 millimeters, 12.7 millimeters and 11.8 millimeters. Suchspacings preferably are used in a non-periodic, non-repeating patternover a length of the belt that includes approximately fifty grooves. Inone example, the pattern established by the belt manufacturing equipmentrepeats after every 47^(th) groove. In another example embodiment, thespacings are selected from 11.2 millimeters, 12.1 millimeters and 12.7millimeters. Those skilled in the art who have the benefit of thisdescription will be able to select appropriate groove spacings toachieve the desired level of smoothness and quietness to meet the needsof their particular situation.

In one example, modeling is used to determine the selected spacingdimensions and pattern. The effects of the grooves are characterizedwith a complex waveform to approximate the input disturbance energy. Thecomplex waveform in one example is determined by sampling beltperformance and developing a suitable function that corresponds to thesampled belt behavior. This input function is included for each cord(i.e., each belt segment between adjacent grooves). The summation of thefunctions are based on the relative phase of the cords. The overallenergy is the sum of each cord's contribution. Therefore, the phasing ofthe cords (i.e., spacings between grooves) determines the overallmagnitude. A Fast Fourier analysis provides an assessment of therelative overall energy level resulting from the belt.

By altering spacings between adjacent grooves, the noise component,caused by contact of the belt assembly with other elevator systemcomponents, such as the sheaves, during system operation, is spread overa broader range of frequencies. Thus, steady state frequencies of noiseare avoided which eliminates the potential for an audible, annoyingtone.

In addition to varying the spacing between the grooves, the inventivearrangement provides the ability to vary the lengths of cord “segments,”which result from certain manufacturing techniques (but are notnecessarily included in the inventive arrangement). A belt assemblydesigned according to this invention may include a series of cordsegments along which the distance between the cord and the jacket outersurfaces varies. The ends of such cord “segments” coincide with thelocation of the grooves. Varying the spacing of the grooves also variesthe length of the segments and therefore varies the pattern of the cordgeometry relative to the jacket outer surfaces. With some example usesof the inventive techniques, the length of the cord segments variesalong the length of the belt.

Because the segments of cord extending between adjacent grooves are ofvarious lengths, there is no periodic, repeated geometric pattern of thecords relative to the jacket outer surfaces. By varying the length ofthe cord segments (i.e., changing spacing between similar distortions inthe position of the cord relative to the jacket outer surfaces) anycontribution to noise or vibration caused by the cord geometry, isreduced or eliminated. By eliminating the periodic feature of the cordgeometry, this invention provides a significant advantage for reducingvibration and noise generation during elevator system operation.

The preceding description is exemplary rather than limiting in nature.Variations and modifications to the disclosed examples may becomeapparent to those skilled in the art that do not necessarily depart fromthe essence of this invention. The scope of legal protection given tothis invention can only be determined by studying the following claims.

1. An elevator belt for supporting weight associated with an elevatorcar and at least partially wrapping about a sheave that moves to causemovement of the elevator car, comprising: a plurality of cords alignedgenerally parallel to a longitudinal axis of the belt, the cords beingadapted to support the weight associated with the elevator car, thecords being spaced apart from each other in a width direction across thebelt; and a jacket over the cords, the jacket including a plurality ofV-shaped grooves on at least one surface of the jacket that extendsacross the width direction of the belt and is adapted to contact thesheave, each groove having only two portions each at an oblique anglerelative to the belt axis, the portions each having one end at an edgeof the jacket and an opposite end at a middle region of the at least onesurface, with the opposite ends of the portions intersecting each otherat an angle to form a peak of the V-shape, the two portions of eachgroove together extending across the entire one surface in the widthdirection of the belt, the grooves being spaced apart such that adjacentgrooves are on opposite sides of a longitudinal position on the belt,the jacket comprising an uninterrupted surface across an entire spacingbetween each one of the V-shaped grooves and a next one of the V-shapedgrooves longitudinally adjacent the one of the V-shaped grooves, theuninterrupted surface having a first surface edge consisting of only twosegments at an edge of the one of the V-shaped grooves and a secondsurface edge consisting of only two segments at an edge of the next oneof the V-shaped grooves, the first surface edge and the second surfaceedge being parallel to each other along an entire length of the edges,the first surface edge and the second surface edge being oriented thesame as each other in a longitudinal direction along the belt.
 2. Thebelt of claim 1, wherein the belt width extends in a direction generallyperpendicular to the longitudinal axis between one lateral edge on thebelt and an opposite lateral edge on the belt.
 3. The belt of claim 1,wherein the longitudinal position extends along a line transverse to thelongitudinal axis.
 4. The belt of claim 1, wherein every portion ofevery groove is on the opposite side of the longitudinal position fromevery portion of every adjacent groove.
 5. The belt of claim 1, whereinevery portion of each groove is at the same oblique angle.
 6. The beltof claim 1, wherein each of the portions is linear and at least a firstone of the linear portions is at a first oblique angle and at least asecond one of the linear portions is at a second oblique angle.
 7. Thebelt of claim 6, wherein each groove has a transition between theadjacent portions, and wherein at least two of the transitions are atdifferent longitudinal positions on the belt.
 8. The belt of claim 1,wherein each groove has a transition at the peak of the V-shape andwherein the peak is at least partially curvilinear.
 9. The elevator beltof claim 1, wherein each of the portions has a first edge along one sideof the portion on the one surface of the jacket and a second edge alongan opposite side of the portion on the one surface of the jacket. 10.The elevator belt of claim 9, wherein the first edges intersect to formone edge of the peak of the V shape and the second edges intersect toform an opposite edge of the peak of the V shape.
 11. An elevatorsystem, comprising: a car that is moveable in a selected verticaldirection; at least one sheave; and a plurality of belts that at leastpartially wrap around the sheave and move about the sheave as the carmoves in the selected direction, the belts being parallel to each otherand moving at the same speed as the car moves in the selected direction,each belt having a plurality of cords aligned generally parallel to alongitudinal axis of the belt and a jacket over the cords, the jacket ofeach belt including a plurality of grooves on at least one surface ofthe jacket that engages the at least one sheave, each groove having aplurality of portions at an oblique angle relative to the belt axis,each groove having at least one transition between adjacent portions,the transitions on a first one of the belts being at differentlongitudinal positions than the transitions on a second one of the beltssuch that the transitions on the first one of the belts contact thesheave at a different time than the transitions on the second one of thebelts contact the sheave as the car moves in the selected direction,every one of the grooves on the first one of the belts including oneportion extending longitudinally at a first oblique angle and anotherportion extending longitudinally in an opposite direction at a secondoblique angle, every one of the grooves on the second one of the beltsincluding one portion extending longitudinally at a third oblique angleand another portion extending longitudinally in an opposite direction ata fourth oblique angle, wherein the first oblique angle is differentthan the second oblique angle.
 12. The system of claim 11, wherein thetransitions on at least one of the belts are curvilinear.
 13. The systemof claim 11, wherein the grooves on at least one of the belts are spacedapart such that adjacent grooves are on opposite sides of a longitudinalposition between the adjacent grooves.
 14. The belt of claim 13, whereinevery portion of every groove is on the opposite side of thelongitudinal position from every portion of every adjacent groove. 15.An elevator belt for supporting weight associated with an elevator carand at least partially wrapping about a sheave that moves to causemovement of the elevator car, comprising: a plurality of cords alignedgenerally parallel to a longitudinal axis of the belt, the cords beingspaced apart from each other in a width direction across the belt, thecords being adapted to support the weight associated with the elevatorcar; and a jacket over the cords, the jacket including a plurality ofW-shaped grooves on at least one surface of the jacket that extendsacross the width direction of the belt and is adapted to contact thesheave, each groove having four portions each at an oblique anglerelative to the belt axis, two of the portions having one end at an edgeof the jacket, and an opposite end at the middle region and intersectingan end of an adjacent one of the portions at an angle to form a peak ofthe W-shape, the four portions of each groove together extending acrossthe entire one surface in the width direction of the belt, the groovesbeing spaced apart such that adjacent grooves are on opposite sides of alongitudinal position on the belt, wherein no other groove portionsintersect with the W-shaped grooves such that the jacket comprises anuninterrupted surface across an entire spacing between each one of theW-shaped grooves and a next one of the W-shaped grooves longitudinallyadjacent the one of the W-shaped grooves, the uninterrupted surfacehaving a first surface edge consisting of only four segments at an edgeof the one of the W-shaped grooves and a second surface edge consistingof only four segments at an edge of the next one of the W-shapedgrooves, the first surface edge and the second surface edge beingparallel to each other along an entire length of the edges, the firstsurface edge and the second surface edge being oriented the same as eachother in a longitudinal direction along the belt.
 16. The elevator beltof claim 15, wherein each of the portions has a first edge along oneside of the portion on the one surface of the jacket and a second edgealong an opposite side of the portion on the one surface of the jacket.17. The elevator belt of claim 16, wherein the first edges of twoadjacent portions intersect to form one edge of one of the peaks of theW-shape and the second edges of the two adjacent portions intersect toform an opposite edge of the peak of the W-shape.